Our economy is driven by the use of fossil fuels. Shortages caused by exhausting oil supplies primarily affect the transport sector of our society and the chemical industry, but secondarily affect all aspects of human activities. As an additional problem, the use of oil supplies has caused the build-up of a high CO2 concentration in the atmosphere.
Energy ultimately comes from the sun and this energy drives photosynthetic process in plants and photoautotrophic bacteria. This knowledge has led to new methods for the synthesis of biofuels. In essence, these processes employ plants and algal species to reduce CO2 to the level of sugars and cell material. After harvesting, these end products are converted to ethanol by yeast fermentation (in the case of crops) or converted chemically to biofuels (in the case of algae). The overall energy conservation of these methods is highly inefficient and therefore demands large surface areas. In addition, the processes are rather labor-intensive, are demanding with respect to water consumption and affect foodstock prices with adverse consequences for food supplies. A more remotely similar process is based on the conversion of solar energy into hydrogen. Also this process suffers from a severely decreased efficiency.
Numerous biotechnological processes make use of genetically engineered organisms in order to produce bulk or fine chemicals, proteins or antibiotics. In many cases, increased production has been obtained by improved gene expression and by optimization of growth conditions. In all processes we are aware of, the initial carbon-precursor has been and still is sugar (notably glucose, but many other mono- and polysaccharides are in use) or related organic substrates: solventogenesis (including butanol and ethanol) and organic acid production (e.g. lactic-, citric- or succinic acid) always starts from glucose, which makes it inefficient as the production process uses a high energy initial compound as substrate.
U.S. Pat. No. 6,699,696 describes a process of producing ethanol by feeding carbon dioxide to a cyanobacterial cell, especially a Synechococcus comprising a nucleic acid molecule encoding an enzyme enabling the cell to convert pyruvate into ethanol, subjecting said cyanobacterial cell to sun energy and collecting ethanol. This system has several drawbacks among others the expression system used is temperature sensitive which demands to adapt the production system for such regulation.
Therefore, there is still a need for an alternative and even improved production process of an organic compound, which do not have all the drawbacks of existing processes.